After you cast create thunderstaff on a normal quarterstaff, the staff must then be mounted in a noisy location, such as a busy marketplace, and left there for 60 days. During that time, the staff gradually absorbs ambient sound. After 60 days, the staff is fully charged and can’t absorb any more sound. At that point, it becomes a thunderstaff, a +1 quarterstaff that has 10 charges. When you hit on a melee attack with the staff and expend 1 charge, the target takes an extra 1d8 thunder damage. You can cast a thunderwave spell from the staff as a bonus action by expending 2 charges. The staff cannot be recharged. If the final charge is not expended within 60 days, the staff becomes nonmagical again.